Explain the front light, back light, top light, side light and high-key, middle-key and low-key of photography.

It is easy to understand that the light levels generated at different positions of the light source form the forward light, side light and so on. For example, when the light source is located on the left or right side of the optical axis, it is called sidelight.

High-profile, also known as bright tone, means that the protagonist's clothing and background are mainly light in large areas, and only the key parts such as the character's head are dark.

Low key is also called dark tone. Contrary to high-profile, the large area of the picture is mainly black or dark, and only the skin of the characters is white and bright, which becomes a prominent part of the picture.

Intermediate tone is also called gray tone, from white to black, with a very rich gray level in the middle, and most photos are intermediate tone.